The government wants U.S. residents to heed a health warning issued by the CDC as the agency looks into a mysterious outbreak of a stomach bug.

The illness, called cyclospora, is reportedly affecting upwards of 250 people across at least six states.

Fox News Medical A-Team's Dr. Marc Siegel shared his professional insight on the bug, one he says is a tiny parasite that is a food-borne illness. It lives on food and in water, he told America's Newsroom co-host Bill Hemmer, adding that the good news is that it cannot be spread through touch.

"If you shake [someone's hand who has it], you won't get it," he said.

Symptoms to look for begin similar to those of the flu, but the illness causes "profound diarrhea," Siegel said. "That's really problematic in the heat."

Cyclospora takes about a week to get, but the silver lining is that once detected, it is treatable with antibiotics. Get more info in the clip above.